Wall Street is salivating for SpaceX’s blockbuster IPO this week, but demand is so high that retail investors may not be able to buy shares at the offering price and will likely have to pay a steep premium once they trading begins.

While SpaceX is the clear industry leader, there are already a number of publicly traded stocks with exposure to different parts of the expanding space economy.

The space sector has come into renewed focus as the U.S. and China race to the moon. Meanwhile, SpaceX also seeks to build a colony on Mars, and the Trump administration plans to create the “Golden Dome” space-based missile shield.

In addition to rocket companies that launch payloads into orbit, others in the sector develop satellites and vehicles or provide space-based services like communications and imagery. Some are recent upstarts, while others have been mainstays for decades.

Elon Musk started SpaceX in 2002 to challenge the dominance of Boeing and Lockheed Martin. By pioneering the development of reusable boosters that can land autonomously, the company slashed launch costs and ramped up its launch cadence—suddenly making low Earth orbit more accessible to a broad range of customers.